Motor



Patented Apr. 7, 1942 MOTOR.

Oliver H. Simmons, Chicago, Ill., assigner to Buell Manufacturing Co.,Chicago, Ill., a corporation of Illinois Application April 5, 1940,Serial No. 328,007

13 Claims.

This invention relates to a single acting fluid pressure motor having apressure operated valve for controlling the admission and exhaust ofmotive fluid to and from the motor cylinder. The invention is of specialutility for a rocker jack motor, namely an upright motor whose pistoncarries ka jack which with the load thereon is reciprocated verticallyby operation of the motor. Such a device may be used under an automobileor motor vehicle for rocking or vibrating the vehicle body or chassisrelative to its supporting springs during greasing, as is desirable topromote effectual penetration of grease between the spring leaves andinto the shackles and spring joints.

Objects of the invention are to provide an improved motor for use as arocker jack motor or under conditions in which the motor piston is movedreversely by a load or byv reaction of a force opposing the workingstroke of the piston;- to provide a single acting fluid pressure motorwith a pressure operated valve which will control the motor eicientlyand in a manner advantageous for the purposes of a rocker jack motor, ashereinafter indicated; and to provide;- such a motor with a pressureoperated valve of practicable, efficient and reliable character.

The invention further pertains in part to certain novel features inreference to the piston and piston rod assembly and the lubrication ofthe cylinder and piston rod.

An illustrative embodiment of the invention in a rocker jack motor ofone practicable construction is shown for example in the accompanyingdrawings. The invention will be de scribed with reference to thedrawings and will be more particularly pointed out and defined in theclaims appended hereto.

In said drawings:

Fig. 1 is a central vertical section of the illustrative rocker jackmotor, showing the valve therefor in position for admitting motive fluidto the working end of the motor cylinder.

Fig. 2 is a partial sectional view on a larger scale showing the valvein position to allow exhaust from the working end of the motor cylinder.

Fig. 3 is a plan View of a valve operating piston.

Fig. 4 is a side elevation partly in section of the motor valve body andconnections therewith.

Fig. 5 is adetail View of a part of a connection with a lateral cylinderport.

Fig. 6 is a View similar to Fig. 5 showing a check valve in saidconnection.

In the drawings, I is the base plate of a rocker yof the motor cylinder.

jack motor comprising the upright cylinder 2 and the jack-carryingpiston 3 working therein. In the specific construction shown, the pistonis aiiixed to the lower end of a tubular piston rod 4 in whichtelescopes a jack section 5 shown as a ratchet bar engageable by holdingdogs 6 pivoted to ears 'I of the collar 8 aflixed to the upper end ofthe piston rod. The jack section 5, which may be lifted to obtain aquick rough adjustment of the jack, is interiorly screw-threaded andengaged by the jack screw 9 having the jack head I0 fixed thereto. Thejack construction shown is but one example of a suitable jack to becarried by the motor piston. At I I there is diagrammaticallyrepresented a load sustained by the jack, which may be considered torepresent so much of the weight of an automobile body as the jack takesfrom the vehicle springs.

A guide for the piston rod may be provided by the sleeve I2 affixed tothe upper end of the cylinder. The piston rod has a loose sliding t inthe guide sleeve, allowing venting oi' the cylinder space above thepiston. Additional venting capacity may be provided by a groove I3 inthe guide sleeve. A desirable construction is shown for connecting themotor piston to the tubular piston rod. As shown, the piston is formedwith a circular recess in which the lower end of the tubular piston rodis tted, and the parts are secured in assembly by a bolt I6 connectingthe piston to a thick washer or plug I4 tted in the piston rod andbutting against a spring locking ring I5 engaging an annular groove inthe piston rod, thereby clamping the piston rod to the piston. The samebolt I6 is utilized to hold the bottom piston plate I1 to the pistonhead. A rubber packing ring I8 is shown clamped between the piston headand bottom piston plate. To the upperside of the piston is secured anoil saturated felt ring I9 for lubricating the cylinder walls. An oillling opening may be provided by a tting 25 in the upper end of thecylinder, said opening being normally closed by its removable screw cap.

Reference will now be made to the pressure operated valve forcontrolling admission and eX- haust of motive fluid to and from thelower end In the drawings, the numeral ZI designates a Valve body, shownformed as one piece except for the attached cap 22. For convenience thevalve body is shown attached to the motor base plate l, though it is notnecessary that it be mounted directly on the motor, as the valve couldbe in either immediate or distant association with the motor. The

valve body contains a motive uid inlet chamber 23 (Fig. 4) into whichmotive uid from a source of supply is introduced through any suitableconnections including a manually operated cut off and throttling valve24 (Fig. 4) and filter 25. Compressed air, being conveniently availableat automobile servicing stations, is preferably utilized as the motivefluid. The pipe 26 shown in Fig. 4 may be assumed, for example, to beconnected by a rubber hose with a source of compressed air for operatingthe motor. The valve 24 in Fig. 4 is normally closed, and opened when itis desired to operate the motor.

Flow of motive fluid to and from the working end of the motor cylinderis controlled by a movable valve member 21 shown as a small piston valvewhich slides in a small bore chamber 28 communicating by the inlet port29 with the motive fluid inlet chamber 23. The valve chamber 28communicates by a lateral port 30 with the so-called cylinder passage 3|in the valve body, namely a passage in communication with the workingend of the motor cylinder. In the specic construction shown the passage3| communicates with the lower end of the motor cylinder through theduct 32 in the motor base plate I. By a lateral port 33, the valvechamber communicates with an exhaust passage 34. The valve 21 worksbetween the inlet and exhaust ports 29 and 33 and in its reciprocationspasses the socalled cylinder port 33. The valve 21 is always exposedduring motor operation to pressure of motive fluid from the inletchamber 23, communicating with the valve chamber by the inlet port 29,and the valve is operated by such pressure to the position shown in Fig.1, thereby admitting motive fluid to the cylinder through the passage 3|and cutting off communication between the cylinder and exhaust passage34. By intermittent application of fluid pressure to a piston 35, motionof which is transmitted to the valve member 21 by the Valve rod 31, theValve is reversely operated to the position shown in Fig. 2, cutting offadmission and establishing connec tion between the cylinder passage 3|and exhaust passage 34. The pressure are'a of the piston 35 is manytimes larger than that of the small piston valve 21 exposed to thepressure of the motive fluid to be admitted. The piston 35, shown havinga piston ring 35, works in a chamber 38 in communication with theexhaust passage 34 through the passages 39 and 48. During exhaust apressure of exhausting fluid is maintained on the piston 35, and thevalve will be held in position for exhaust so long as the force on thepiston 35 exceeds that on the small piston 21.

To prevent building up a back pressure under the piston 35, the space 4|under the piston communicates with the atmosphere through the outletport 42. The Valve body 2| may be formed with a boss 43 limiting themotion of the piston 35 in the direction for actuating the valve toexhaust position. The space around said boss 43 is preferably filledwith a porous packing 44 of wool, felt or other suitable air-lteringmaterial. The chamber 33 in which the piston works is suitably vented;provision for venting being made in this instance by the gap 45 in thepiston ring. The piston preferably comprises a pair of spaced discsholding between them the expansible piston ring 3S in contact with thecylinder walls of the chamber 38. The piston ring 36 may be of Bakeliteor the like. Discharge of fluid from the chamber 38 through the gap inthe piston ring and through the air-filtering medium 44 is sufcientlyrestricted to insure backing up of exhaust pressure in the exhaustpassages 34, 39, 40 during exhaust. In the specific construction shown,the piston 35 is xed to the upper end 0f the valve rod 31 which slidesin a bore in the valve body, said valve rod being reduced in diameter at45 to allow flow of exhausting iiuid around the valve rod, therebyproviding the piston head 21 working in the chamber 2S which is acontinuation of the bore in which the upper part of the valve rod isguided.

A pipe or tube 41 is shown connected with the valve body by the screwplug 48. The passage through said pipe and screw plug communicates at 49with the exhaust passage 34 and with the passage 39 leading to thepiston chamber 38. The passage in said pipe 41 is connected with themotor cylinder through a lateral port 50 so located that the motorpiston will pass said port in its working or up stroke; whereupon motiveiluid discharging from the working chamber of the motor cylinder intothe passage in pipe 41 will cause a quick pressure impulse or pull? inthe piston chamber 38 for operating the motor valve reversely to theexhaust position shown in Fig. 2. As shown in Fig. 2, the motor pistonin its up stroke has just passed the port 50, with the result that themotor valve has been operated to the exhaust position shown, and thecylinder now commences to exhaust from its lower end. As the motorpiston descends, it covers the port 5D, and while said port is coveredthe exhaust from the lowei` end of the motor cylinder takes placethrough the piston chamber 38. As the descending piston passes below theport 50, the exhaust can take place partially through the piston chamber38 and partially through the port into the cylinder space above thepiston. Provision is made for suitably restricting the exhaust throughthe pipe 41 and port 50, as for example by forming the port 50 so smallin relation to the exhaust passages in the Valve body as to insurebacking up of pressure in said passages during exhaust. As shown in Fig.5, the

lateral cylinder port 50 is connected with the pipe 41 through a fitting5| the passage in which may be restricted or cut oil by a suitablymanually operated valve 52, preferably of the needle valve type.

The operation of the motor as thus far described will be brieflysummarized as follows: Assuming that the Valve 24 (Fig. 4) in the motivefluid supply line is opened when the motor piston is at the bottom ofits stroke, the pressure operated motor controlling Valve is immediatelyactuated to the position shown in Fig. 1 for admitting motive fluid tothe lower end of the cylinder, such actuation being by pressure of themotive fluid from the source of supply on the small Valve piston 21. Inits working or up stroke the piston passes the port 50, whereupon apressure impulse is created in the chamber 38 by discharge of motivefluid from the Working chamber of the motor through the port 50 into thepipe 41 which communicates through the passages 39 and 43 with saidchamber 38. The pressure in chamber 33 upon the valve piston 35 ofrelatively large area immediately actuates the valve to the positionshown in Fig. 2, cutting off admission and establishing exhaustconnections. While the descending piston covers the port 59, exhaustfrom the lower end of the motor cylinder takes place through the chamber38, the discharge of exhausting fluid from said chamber being restrictedby the small gap 45 through Vwhich the chamber is vented and by thepacking material 44 through which the exhausting iiuid passes. When thedescending piston passes below and uncovers the port l), the exhaust maytake place partially through the pipe 41 and port 50 into the motorcylinder space above the motor piston, such exhaust being suiiicientlyrestricted to preserve a pressure of exhausting uid in the chamber 38.This pressure in chamber 38 will keep the motor valve in the exhaustposition so long as the force on thepiston 35 exceeds the opposing forceon the small valve piston 22. Preferably the device is so designed (asto the ratio of opposing pressure areas of the motor valve andrestriction of outlet from the exhaust passages) as to require asubstantial load on the jack to impose a sufficient pressure on theexhausting fluid to maintain the motor valve in exhaust position; thoughthe load so required may be only a small proportion of the maximum loadsustained by the jack during operation. For example, the motor may bedesigned so that, when operating with motive fluid at a pressure ofabout 100 pounds, the valve will be operated from exhaust position tothe admission position when the diminishing load on the descending jackfalls below about 100 pounds.

In Fig. l a load sustained by the jack is diagrammatically indicated atIl. This may represent the weight or partial weight of an automobilebody supported by the vehicle springs except to the extent that theweight may be taken by the rocker jack. Let it be assumed, for example,that the vehicle springs support the load in the position shown in Fig.1, or in other words that the load would be supported by the springs inthe position shown at Il if the rocker jack were removed from under it.Let it be assumed that the rocker jack has been placed under the loadwhile the motor piston is at the bottom of the motor cylinder, and whilethe valve 24 (Fig. 4) in the motive iiuid supply line is closed, andthat the jack has been adjusted to leave a clear- -ance of about a halfinch or so between the jack head I0 and the load Il. It will beunderstood that the jack head I0 may be equipped with any suitablesaddle bar (not shown) to bear up in lifting engagement with the centerbars or with one of the cross bars of the automobile chassis, and thatthe jack may have been adjusted to leave a clearance between such saddlebar and the part to be lifted. Thus it may be assumed that beforestarting the motor operation there is a clearance between the jack headil) and the load Il (or between a saddle bar on the jack head and thepart of the vehicle to be lifted) equal to the distance between the headof the piston bolt I6 and the bottom of the cylinder. Now when the valve24 (Fig. 4) in the motive fiuid supply line is opened, the motor willoper-ate in the manner previously explained, but the first part of thefirst working or up stroke of the motor piston will be consumed intaking up the aforesaid clearance and bringing the jack head l0 intoposition for lifting the suspended load I I with relation to itssupporting springs. Continuing its up stroke, the motor piston will liftup the load until the piston passes the cylinder port 50, whereupon thepiston will commence to descend and exhaust will take place from thelower end of the cylinder. As the piston descends, the weight of theload Il is being gradually taken up by the vehicle springs, so that asthe piston approaches the position shown in Fig.

l there ceases to be enough loadl on the piston for imposing on theexhausting motive fluid a suicient pressure to hold the motor valve inexhaust position; hence the valve will resume position for -admittingmotive fluid to the lower end of the cylinder. Thus the piston will notdescend clear to the bottom of the cylinder, nor quite to the positionwhere it commenced to take up the load on its first up stroke. In shortthe working stroke of the piston will automatically accommodate itselfto the original clearance between the jack head and the load, and willbe less than the full possible working stroke by an amount somewhat inexcess of the clearance aforesaid; with the desirable results that thejack will not be released from the vehicle body, and the reciprocationof the load will be from a point where a certain load is carried by thepiston. It will be understood that if the original clearance between thejack head and the load (or between the saddle bar carried by the jackhead and the part of the automobile body or chassis frame to be lifted)should be only a slight clearance, the motor piston would have anaccordingly longer working stroke, and if the said clearance should bean inch or more the motor piston would have an accordingly shorterstroke; so that it is easily possible, merely by adjusting the jack toprovide more or less clearance between it and the load, to control thestroke of the motor piston, and accordingly to vibrate or move up anddown the lo-ad with either short or slight up and down movements orlonger up and down movements. While the load H in Fig. 1 has beenassumed to be supported by vehicle springs in the position shown in Fig.1, it may also be assumed to have been'raised from a somewhat lowerposition by the motor; so that Fig. 1 may be considered either `asrepresenting the rocker jack motor in the operation of reciprocating theload carried thereby, or as representing the motor when it firstcommences to lift the load relative to its support by the vehiclesprings.

Cessation of operation of the motor is of course accomplished by closingthe valve 24 (Fig. 4) in the motive fluid supply line. If the rockerjack is to be removed from under the motor vehicle, or if it is desiredto release the jack from the load, the valve 24 should be closed whilethe motor piston is descending, the motor controlling valve being in theexhaust position shown in Fig. 2. Upon closing the valve 24, -a smallamount of motive fluid will be trapped in the inlet passage 23 (Fig. 4)and lower end of the chamber in which the valve piston 21 Works. As thepiston descends, the small amount of air so trapped will push up themotor 'valve to the position shown'in Fig. l, whereupon the valve isimmediately returned to the exhaust position by the motion of a spring53 arranged in the chamber 38 and acting on piston 35. The motor pistonmay therefore descend to the bottom of the motor cylinder, allowingrelease of the jack from the load.

It is sometimes desirable to use a rocker jack for the purpose of anordinary pneumatic lifting jack, as for example where an automobile axleis to be lifted and held raised to permit removal of a tire. This can beaccomplished with the illustrative rocker jack by closing the valve 52(Fig. 5), with the effect of closing the port 5U and thereforepreventing operation of thel motor controlling valve to position toallow exhaust. Assuming the valve 52 (Fig. 5) to be closed, and thevalve 24 (Fig. 4) to be opened when the piston is at the bottom of thecylinder, the piston with the load above it would simply be raised andheld in raised position. This condition would continue until the valve52 is reopened to cause reverse action of the' pressure operated motorcontrolling valve to position to allow exhaust.

An advantage among others in having exhaust take place through the port50 into the cylinder space above the piston is that as the pistondescends, and as the oil saturated felt ring I9 of the descending pistonpasses the port 5G, the jet of exhausting fluid issuing therefrom willatomize and spray oil against the piston rod, keeping the latterlubricated. Exhaust into the upper chamber of the cylinder also issubstantially silent, and exhaust through the port 5l) in addition tothe exhaust through the chamber 38 is desirable to provide additionalexhaust after the weight of the automobile body carried by the motorjack has been largely transferred to the supporting springs of thevehicle. However the invention in its broadest aspect does not dependupon an arrangement providing for an exhaust into the motor cylinder, itbeing sufficient for the broad purpose of the invention to establishcommunication between the working chamber of the motor cylinderand thechamber 3B of the valve operating piston 35 as the motor pistoncornpletes or is about to complet-e its working stroke. It is thereforewithin contemplation to employ, if desired, a spring actuated checkvalve normally closing the port 50, such valve adapted to open onlyunder pressure of motive uid in the working chamber of the motorcylinder. Such a valve is shown in 54 in Fig. 6. If such check valveshould be employed, the port 5i! would open when the motor piston movesabove it, but would be closed at all times except when the port or apart of the port is below the lower edge of the packing ring I8 of thepiston. In that case the exhaust would take place entirely through thechamber 38 or in part through said chamber and such additional exhaustpassage, if any, as might be provided.

The motor piston is to be considered as above the port 5U when it issufficiently above the lower side of the port to cause a pressure in thechamber 38 for operating the motor valve to position for admission.Inasrnuch as the piston of the illustrative motor is equipped with thepacking ring i8 depending below the piston head, the said piston of theillustrative motor is to be considered as above said port 50 when thelower edge of the packing ring I8 is sufficiently above the lower sideof said port to cause said effective pressure in the chamber 38.

If the motor should be equipped with a type of jack capable of manualoperation for load lifting, and if before operation of the motor andwhile its piston is at the bottom of the cylinder the `iack should havebeen manually operated to lift the automobile body relative to itssupporting springs, then of course in the ensuing operation of the`motor the piston would always descend to the bottom of the cylinder,after which the pressure in the exhaust passages would of course ceaseor fall so low as to permit the motor controlling valve to resumeposition for admission. To release such type of jack from the load,after stopping the operation of the motor, would of course beaccomplished by reverse manual operation of the jack to lower it fromthe suspended load.

Obviously detail changes may be made in the structural features of theparts described without changing the essential character of the motor'ordeparting from the principle of the invention; it being understood thatthe invention is not limited to the specific embodiment selected forillustration, and that reservation is made of such variations,modifications, and mechanical equivalents of structural parts as fallwithin the spirit and perview of the claims.

I claim as my invention:

i. In a rocker jack motor of the single acting fluid pressure typecomprising an upright motor cylinder and jack-carrying piston workingtherein. a valve operated by pressure of motive fluid from a source ofsupply for admitting such iiuid to the motor and reversely operable byopposing pressure to cut off admission and to establish exhaustconnections, said valve having a relatively small pressure area alwaysexposed during motor operation to said first mentioned pressure and amany times larger opposing pressure area exposed during exhaust topressure of exhausting fluid, there being a passage through which thecylinder exhausts having a chamber in which said larger area is soexposed, said passage having restricted outlet, and a lateral cylinderport connected with said passage and which the motor piston passes inits working stroke with the effect of creating in said chamber a suddenpressure on said larger area which forces the valve to position forexhaust, the relationship between said areas and restriction of now ofexhausting fluid being such that said pressure of exhausting fluid onsaid larger area holds the valve in exhaust position while thedescending piston sustains a load in excess of a certain value butbecomes insuflioient for said purpose when said load falls below saidvalue, whereby in using the device for rocking or vibrating anautomobile body, under such conditions that the first up stroke of thepiston lifts the body from a position in which it was supported entirelyor substantially entirely by its springs, the ensuing down stroke willbe sufficiently less than said first up stroke to prevent release of thejack from the automobile body.

2. In a rocker jack motor of the single acting fluid pressure typecomprising an upright motor cylinder and jack carrying piston workingtherein, a pressure operated valve for controlling admission and exhaustof motive fluid to and from the motor, said valve having a relativelysmall pressure area always exposed during motor operation to pressure ofthe motive fluid to be admitted and having a relatively large opposingpressure area.there being a passage through which the cylinder exhaustsfrom its lower end and a chamber in which pressure acts on said largearea in opposition to the pressure on said small area, and a lateralcylinder port which the motor piston passes in its up strokecommunicating with said chamber whereby pressure therein to operate thevalve to exhaust position is created when the motor piston is above saidport, there being restriction of outlet of exhausting fluid to maintaina pressure thereof in said chamber during exhaust whereby to hold thevalve in exhaust position, said port affording an additional outlet forexhausting fluid after the piston in its return stroke has passed anduncovered said port, the arrangement being such as to require impositionof at least some load on the jack in order to maintain a sufficientpressure of exhausting iiuid on said larger area to hold the valve inexhaust position.

3. In a single acting fluid pressure motor com- 'prising a cylinder andpiston working therein, a valve operated by pressure of motive fluidfrom a source of supply for admitting such uid to the working end of thecylinder, said valve having relatively large and small pressure areasthe smaller of which is always exposed during motor operation to saidpressure, a vented chamber in which fluid pressure acts on said largearea in opposition to the pressure on said small area, a passage incommunication with said chamber and with a lateral port in the motorcylinder which is passed by the motor piston in its working stroke, thevalve being reversely operable to cut oi admission by pressure createdin said chamber on said large area in consequence of said passing ofsaid port, and an exhaust passage connecting the working end of thecylinder with said vented chamber while the valve is in its reverse`position, the valve being maintained in such reverse position so long asthe force on said large area exceeds the opposing force on said smallarea, the exhaust being through said vented chamber While said port iscovered by the motor piston on its return stroke and thereafter partlythrough said vented chamber and partly through said port and non-Workingend of the cylinder.

4. In a single acting uid pressure motor comprising a cylinder andpiston working therein, a lateral cylinder port which the motor pistonpasses in its Working stroke, a pressure operated valve for controllingadmission and exhaust of motive fluid to and from the working end of thecylinder, said valve comprising a relatively small piston exposed topressure of motive uid from a source of supply and operable thereby toposition for admission, a relatively large piston by pressure on whichthe valve is operable to position to cut off admission, there being anexhaust passage connected with the working end of the cylinder when thevalve is in position to cut off admission, a vented chamber in whichsaid relatively large piston works, a passage in communication with saidchamber and connected with said lateral port of the motor cylinder,whereby pressure for reversely operating the valve is created in saidchamber when the motor piston in its working stroke passes said port,said exhaust passage being in communication with said chamber and withsaid lateral cylinder port, the exhaust taking place through saidchamber while the motor piston in its reverse stroke covers said portand thereafter taking place at least in part through said port into thecylinder space above the motor piston and being restricted, and thevalve being held in exhaust position so long as the force on said largepiston exceeds the opposing force on the small valve piston.

5. In a single acting uid pressure motor having a lateral cylinder portthrough which motor exhaust takes place at least in part, a ring ofoilsaturated air-permeable material carried on the upper side of themotor piston and which moves across said port, whereby the jet ofexhausting iluid can atomize oil from said material and blow it againstthe piston rod.

Gf. In 'a uid pressure motor, a tubular piston rod and piston securedthereto in the manner described, said rod having an internal annulargroove and a locking ring sprung therein and a part retained therein bysaid ring, and a clamp bolt connecting said part with the piston andthereby clamping the piston rod to the piston.

7. In a single acting iiuid pressure motor comprising a cylinder andpiston Working therein, a valve constantly urged by live fluid pressureto position for admitting motive fluid to the cylinder and reverselyoperable by opposing pressure to position for exhaust, there beingmotive uid inlet and exhaust passages connected in alternation with thecylinder by operation of said valve, a chamber in constant communicationwith said exhaust passage in which pressure acts on said valve inopposition to said first mentioned pressure and through a larger area ofpressure application than that through which said lirst mentionedpressure acts, and a lateral cylinder port which the motor piston passesin its Working stroke and through which when so passed working fluid istemporarily released, said port communicating with said chamber in whichupon such release a sudden pressure is created which forces the valve toposition for exhaust, there being no communication between said chamberand the Working chamber of the cylinder except temporarily through saidport and thereafter through said exhaust passage during the period ofexhaust, there being restriction of outlet of exhausting uicl and thepressure thereof holding the valve in exhaust position so long as theforce thereby exerted on the valve exceeds the opposing force thereon.

8. In a single acting uid pressure motor comprising a cylinder andpiston working therein, a valve constantly urged by live uid pressure toposition for admitting motive fluid to the cylinder and reverselyoperable by opposing pressure to position for exhaust, there beingmotive fluid inlet and exhaust passages connected in alternation withthe cylinder by operation of said valve, said exhaust passage havingrestricted outlet, a chamber in .constant communication with saidexhaust passage in which pressure acts Aon said valve in opposition tosaid rst mentioned pressure and through a larger area of pressureapplication than that through which said iirst mentioned pressure acts,and a lateral cylinder port which the motor piston passes in its workingstroke and through which when so passed Working fluid is temporarilyreleased, said port communicating with said chamber in which upon suchrelease a sudden pressure is created which forces the valve to positionfor exhaust, said cylinder port `affording an additional outlet fromsaid exhaust passage after the motor piston in its return stroke haspassed and uncovered said port, the valve being held in exhaust positionby the pressure of exhausting fluid so long as the force thereby exertedon the valve exceeds the opposing force thereon.

9.. In a single acting uid pressure motor cornprising a cylinder andpiston Working therein, a Valve constantly urged by live fluid pressureto position for admitting motive fluid to the cylinder and reverselyoperable by opposing pressure to position for exhaust, there beingmotive fluid inlet and exhaust passages connected in alternation withthe cylinder by operation of said valve, said exhaust passage havingrestricted outlet, a chamber in constant communication with said exhaustpassage in which pressure acts on said valve in opposition to said firstmentioned pressure and through a larger area of pressure applicationthan that through which said rst mentioned pressure acts, and a lateralcylinder port which the motor piston passes in both its working strokeand return stroke and through which when passed by the piston in itsworking stroke the working chamber of the cylinder temporarilycommunicates with said first mentioned chamber in which is consequentlycreated a sudden pressure which forces the valve to position forexhaust, and a check valve normally closing said port and adapted toopen only under the pressure of the Working fluid in the Working chamberof the cylinder, the valve being held in exhaust position by thepressure of exhausting fluid so long as the force thereby exerted on thevalve exceeds the opposing force thereon.

l0. In a single acting fluid pressure motor comprising a cylinder andpiston working therein, a valve constantly urged by live fluid pressureto position for admitting motive fluid to the cylinder and reverselyoperable by opposing pressure to position for exhaust, there beingmotive fluid inlet and exhaust passages connected in alternation withthe cylinder by operation of said valve, said exhaust passage havingrestricted outlet, a Vented chamber included in said exhaust passage andin which pressure acts on said valve in opposition to said firstmentioned pressure and through a larger area of pressure applicationthan that through Which said rst mentioned pressure acts, and a lateralcylinder port connected with said exhaust passage and which the motorpiston passes in its Working stroke with the effect of creating in saidchamber a sudden pressure which forces the valve to exhaust position,the valve being held in exhaust position so long as the force exertedthereon by pressure in said chamber exceeds the opposing force thereon,the Y exhaust from the cylinder taking place through said vented chamberWhile the piston in its return stroke covers said port and thereafterpartly through said chamber and partly through said port and thenon-Working end of the cylinder.

ll. In a single acting fluid pressure motor comprising a cylinder andpiston working therein, a valve comprising a small piston forcontrolling admission and exhaust of motive fluid to the cylinder, therebeing motive fluid inlet and exhaust passages connected in alternationwith the cylinder by operation of said small piston, a chamber incommunication With said inlet passage in which said small piston works,said small piston being constantly urged by the inlet pressure in saidchamber to position for admission, pressure operated means of greaterarea than the pressure area of said small piston for operating it toposition for exhaust, a chamber in which said means Works and which isin constant communication with said exhaust passage and connectedthereby with the working end of the cylinder when the Valve is inexhaust position, the pressure in said second mentioned chamber on saidmeans being in opposition to said first mentioned pressure on the smallpiston, and a lateral cylinder port connected With said exhaust passageand which the motor piston passes in its Working stroke with the effectof creating in said second mentioned chamber a sudden pressure on saidmeans which forces the small piston to position for exhaust, the smallpiston being held in exhaust position so long as the force on said meansexceeds the opposing force on the valve.

l2. In a single acting fluid pressure motor comprising a cylinder andpiston Working therein, a valve comprising a small piston forcontrolling admission and exhaust of motive fluid to the cylinder, therebeing motive iiuid inlet and exhaust passages connected in alternationwith the cylinder by operation of said valve, a chamber in communicationwith said inlet passage in which said valve Works, the valve beingconstantly urged by the inlet pressure in said chamber to position foradmission, pressure ope"- ated means of greater area than the pressurearea of said valve for operating it to position for exhaust, a chamberin which said means Works and which is in constant communication withsaid exhaust passage and connected thereby With the working end of thecylinder when the valve is in exhaust position, the pressure in saidsecond mentioned chamber on said means being in opposition to said firstmentioned pressure on the valve, and a lateral cylinder port incommunication with said second mentioned chamber and which the motorpiston passes in its working stroke with the effect of creating in saidsecond mentioned chamber a sudden pressure on said means which forcesthe valve to position for exhaust, the valve being held in exhaustposition so long as the force on said means exceeds the opposing forceon the valve, said exhaust passage having restricted outlet and saidport affording additional outlet for exhausting fluid after the motorpiston in its return stroke has passed and uncovered said port.

13. In a single acting fluid pressure motor comprising a cylinder andpiston Working therein, a valve comprising a small piston forcontrolling admission and exhaust of motive fiuid to the cylinder, therebeing motive fluid inlet and exhaust passages connected in alternationwith the cylinder by operation of said valve, a chamber in communicationwith said inlet passage in which said valve Works, the valve beingconstantly urged by the inlet pressure in said chamber to position foradmission, pressure operated means of greater area than the pressurearea of said valve for operating it to position for exhaust, a ventedchamber in which said means Works and which is connected by said exhaustpassage with the Working end of the cylinder when the valve is inexhaust position, the pressure in said vented chamber on said meansbeing in opposition to said first mentioned pressure on the valve, and alateral cylinder port connected with said exhaust passage and which themotor piston passes in its working stroke with the effect of creating insaid vented chamber a sudden pressure on said means Which forces thevalve to position for exhaust, the valve being held in exhaust positionso long as the force on said means exceeds the opposing force on thevalve, the cylinder exhausting through said vented chamber while thepiston in its reverse stroke covers said port and thereafter exhaustingpartly through said vented chamber and partly through said port and thenon-Working end of the cylinder.

OLIVER H. SIMMONS.

